Secondary contact spring for plug cut-outs



Dec. 30, 1930. E. HAWLEY 1,787,109

SECONDARY CONTACT SPRING FOR PLUG CUTOUT$ Filed July 6, 1929 7/6; By mAttorney Patented Dec. 30, 1930 UNITED STATES EDGAR LEE HAWLEY, 0]!ATLANTA, GEORGIA snconnan'r con'racr srnrn'e ron PLUG cur-oursApplication filed July 6, 1929. Serial No. 876,449.

This invention relates to plug cut-outs, and has as its primary objectthe provision of an improved secondary contact spring for such plugcut-outs.

The principal object of this device is the provision of an improvedsecondary contact spring for plug cut-outs, which will prevent thecompletion of an electrical circuit between the lug and the contacts ofthe plug cut-out t rough the medium of a coin or other like copperinsertion disposed between the fuse plug contact and the base contact sothat a complete circuit will be closed between the fuse plug contact andthe other contact member located within the cut-out for completing acircuit.

Other objects and advantages of this invention will become apparentduring a study of the followin description, taken in conjunction with te accompanying drawings, wherein:

Figure 1 is a view partly in section and part1 in elevation of a cut-outforfuse and showing the application of my improved secondary contactsprin therewith.

Figure 2 is a front e evation of the cutout with the fuse removed.

Figure 3 is a perspective view of my improved secondary spring contact.

Figure 4 is a rear elevation of the socket for receiving the fuse plu 1With reference more 1n etail to the drawings, it will be seen that myimproved cutout designated generally by the reference character Aconsists of a substantially rectangular base block designated generallyby the reference character 5, and 1t 1s to be understood that this block5 may be made of porcelain or any other suitable material. This block 5is provided with a substantiall rectangular recess 6 extending inwardlyom one face of the block as clearly su ested in Figure 1.

0 cover the recess 6 I provide a substantially rectangular sha ed plate7 of bakeliteor any other suitab e composition, or if desired, metal,the material forming this plate being left to the desire of themanufacturer. This plate 7 which may be termed the cover plate isprovided with a circular opening 8 formed therein and communicating withthe recess 6 formed in the block. Located within the recess 6 of theblock5 adjacent the upper end of the recess there is provided astationary contact member 9, this contact member being suitably fixed tothe rear wall of the recess 6, and the outer face of the contact memberis substantially concave as suggested in Figure 1.

My invention per se consists of a secondary contact member whichconsists of an elongated flexible spring steel strip 10, which spring 10at its lower end is offset laterally, said ofiset portion being curvedoutwardly as suggested at 11. This outwardly curved offset portion 11 ofthe spring 10 is apertured as at 12, and the curved oilset portlon 11 issuitably received in a recess or otherwise imbedded in the inner face ofthe cover plate 7 adj acent the lower end of the cover plate and a bolt13 extends through the cover plate 7 and the aperture in the ofi'set 11and lock nut 14 is threadedly engaged on the iImer end of the bolt 13and bears against this oflt'set 11 f(1)r mgintaining the same in therecess of the p ate At its upper end the spring 10 is provided with acontact member 15, which contact member has a rounded face 16, saidcontact member 15 being complemental to the stationary contact member 9as suggested in Figure 1. As shown, the contact member 15 extendslaterally from the upper end of the spring 10 from the inner face of thespring, while intermediate the ends of the spring 10 the same has formedthereon and extending or disposed on the opposite face thereof asubstantially disc-like contact member 17.

This disc-like contact member 17 has its inner face bevellel assuggested as at 18 and is provided on the bevelled face with anextension 19 which extends through the spring 10 to project laterallyfrom the opposite face of the spring and in the samedirection as thecontact member 15. 20 represents a flexible conductor which iselectrically connected with the contact 17 through the medium of theextension 19 of the contact and at its opposite end is electricallyconnected with the contact member 15. This flexible conductor as shownis preferably crimped. lhe contact member 17 is located on the spring 10on that portion of the spring opposite the open ng 8 formed in the coverplate 7 so that under normal conditions and due to the flexibility ofthe spring and its offset 11, the spring will be urged inwardly towardthe inner face of the plate 7 thus permitting the said contact member 17to extend within the opening 8.

Secured to the outer face of the cover plate 7 is a suitable fuse socket21 and this fuse socket 21 is of theordinary socket construction, withthe exception that the socket is open at both its front and rear andextending radially from the socket adjacent its open ends the same has aplurality of spaced ears 22, which ears 22 are apertured and extend fromdiametrically opposite sides of the socket, to constitute attachingears, while the third ear 23 is bent downwardly upon itself as suggestedin Figure 1 and constitutes a connector for an electrical conductor.

Suitable screws 22' are received through the apertures in the attachingears 22 to be screw threadedly engaged with the plate 7 as suggested inFigure 2. A. screw 2%, has the head thereof imbedded in the cover plate7 and the shank thereof extending laterally from the cover plate andthrough the apertures in the ear 23 and a nut is threaded on the outerend of the screw so that an electrical conductor wire may be heldwithinthe space between the body of the ear audits downwardly bentportion.

A conductor 26 is connected at one end with the stationary contact 9 asat 27, and at its recess 29 formed on the outer face of the block 5adjacent the lower end of the block, and a screw 30 passes through theupper portions of the legs of the U-shaped connector 28 and through thelower end of the conductor member 26 for screw-threaded engagement withan internally threaded socket of a suitable block 31 imbedded in theblock 5 and extend ing inwardly from the rear face of the block.

When a fuse 3 1 is properly screwed into the fuse socket 21, theprotruding contact 34 of the fusewill engage the contact 17 of thespring 10 and force the latter inwardly to dispose the contact 15 inengagement with the stationary contact 9 of the conductor 26. Thecircuit will thus be completed between the connectors 23 and 28 in anobvious manner.

As is well known to complete a circuit be tween the contact of the fuseplug 33 and the base contact 17 it has often been the practice to inserta coin such as a penny between said contacts which of course results inthe backing or short-circuiting of plug cut-outs,

this usually being done by some layman in to obtain light afteroverloaded irreaioe fuse is blown and not realizing that he is doingaway with the protection provided for the fuse, usually forgetting toremove the penny, and re lace with a good fuse. In so doing, he is 0course subjecting his property to the risk of fire when other troublemay arise in the circuit.

However, by my construction the completion of the circuit through theintermediacy of a' penny or like copper disc is prohibited sinceobviously, in the contemplated form of the invention and in actualpractice the opening 8 is of a diameter as to prevent the insertion of apenny within the opening, the diameter of the opening being intended tobe such as to only accommodate the protruding contacts of the fuse 83.Likewise the base contact 17 carried by the spring 10 may be of a sizemerely enabling contact thereof with the contact member of the fuseplug.

Obviously then, if a penny be inserted between the first contact 17 andthe contact member of the fuse plug 33, a circuit would be completedbetween the plug and the base contact 17, but since the penny is notpermitted to be pushed through the opening 8, the movable contact 15carried by the spring 10 may be maintained out of electrical connectionwith the stationary contact 9 since no pressure is exerted upon thespring forcing the same inwardly so that the last mentioned contacts mayengage one with another for completing the circuit.

From the foregoing, it will be seen that I have provided. a thoroughlyreliable and practical secondary spring contact for fuse plug cut-outsand that the same is positive in operation, simple in construction,inexpensive to manufacture, and otherwise well adapted for the purposedesired.

Even though I have herein shown and described the preferred embodimentof my invention, it is to be understood that the same is susceptible tochanges fully comprehended by the same and by the scope of the appendedclaim.

Having thus described my invention, what I wish to claim as new is:

A plug cut out comprising a fuse box having, a recess and a fixedcontact in the recess, a cover for said recess having a substantiallysmall central aperture, a fiat spring disposed upon the inner face ofsaid cover and extending diametrically of the central aperture, saidspring having one end secured to the cover and being flexed to normallylie flat against the cover, a pair of contacts mounted on said springand extendin oppositely therefrom, one of said contacts eing positionedadjacen the free terminal of the spring for engagement with the fixedcontact of the recess when the spring is flexed outwardlyfrom the cover,and the other contact bein positioned intermediate the ends of thespring and normally extending through the aperture of the cover forengagement with a fuse, a flexible conductor electrically connecting thesaid contact of the spring, a fuse socket mounted on the outer face ofsaid cover 5 and over the central aperture thereof, said socket havingits bottom end open to expose the said aperture and said fuse-contactmember of the spring, and a connector on said socketfor an electricalconductor.

10 In testimony whereof I aflix my signature.

EDGAR L. HAWLEY.

